I have not used ProRes yet, but this is what Apple say about it in their white paper:
[i]For years now, Final Cut Pro editors have relied on HD formats such as DVCPRO-HD and
HDV for native, real-time multistream editing. The efficiency and image quality of these
workflows are excellent for content that originates with and can be finished natively in
these formats. But such formats were designed under significant camcorder engineer-
ing constraints, so they limit the full quality that can be carried in an HD signal.
As technology advances, higher-quality HD signals are becoming more common.
Examples include scanned film for Digital Intermediate workflows, live events recorded
directly to disk, more advanced HD-SDI editing decks with little or no compression, and
a new generation of emerging camcorder formats. Users need a new, compact HD
format designed specifically for post-production.
At the highest end of the HD quality spectrum, Final Cut Pro supports uncompressed
HD as a real-time editing format. But the high-bandwidth, RAID-storage requirements
of uncompressed HD are daunting for most users' budgets and put it out of reach of all but the largest post-production facilities and high-budget productions.
Enter Apple ProRes 422, a new format designed for pristine HD quality, economical
hardware configurations, yet high-performance, multistream Final Cut Pro real-time
editingfor both high-definition (HD) and standard-definition (SD) formats. Apple
ProRes 422 features:
-The quality of uncompressed HD at data and storage rates lower than uncompressed SD.
- Performance comparable to or better than the existing HD codecs in Final Cut Pro.
- The ability to work with HD on slower drives, and with more users on shared storage.[/i]
Hope that helps.Cheers